Speed change pulley bracket support



Sept. 21, 1954 Filed June 17, 1952 R. D. PHARES SPEED CHANGE PULLEY BRACKET SUPPORT 2 Sheets-Sheet l Sept.

R. D. PHARES SPEED CHANGE PULLEY BRACKET SUPPORT Filed June 17, 1952 45px; w, 4/

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2 Sheets-Sheet 2 INVENTOYR. 556/7 Q /%'0/1J BY Z M Patented Sept. 21, 1954 UNITED STATES PATENT OFFICE SPEED CHANGE PULLEY BRACKET SUPPORT Robert D. Phares, Phoenix, Ariz.

Application June 17, 1952, Serial No. 294,018

This invention pertains to speed change pulley bracket supports for drill presses having frames with vertical columns supporting a drill head frame which has a vertical spindle positioned within its fore end on the fore side of the column, and a motor having a vertical shaft positioned on the opposite or aft side of the column.

This application is a continuation inpart of my previous application designated Serial Number 161,301, filed May 11, 1950, now abandoned.

Drill presses of this type have heretofore been equipped with cone differential V-belt pulleys on the upper ends of the spindle and motor shaft, and speed changes were obtained by shifting the belt. Later it was recognized that the cone pulleys did not give a suflicient range of speed variation, and differential changes of various types were tried. In mounting these differential type speed change pulleys a bracket was provided which pivoted on a bearing, havingan axis substantially in alignment with the axis of the vertical column. It has been found that thearcuate travel of the speed change pulley mounted on such a bracket caused the belts used in connection with the differential speed change pulleys to be too tight in some positions and too loose in others. Furthermore, the-re was no provision made for vertical adjustment of the belts to accommodate the vertical change of position which took place when the shiftable central portion of the speed change pulley moved vertically on its supporting shaft.

In view of the foregoing one of the objects of this invention is to provide a simple cheaply made bracket for mounting a shiftable speed change pulley assembly, of the type having two pulley cones betweenwhich a shiftable pulley part moves vertically, on or above the column of a drill press of the type described, so that its travel will be substantially in a straight line between the axis of thespindle shaft and motor shaft.

A second object is to provide a simple and cheap bracket for shiftable speed change pulleys, of the type mentioned, which when mounted on and over the drill press frame column will not only move the speed change pulley assembly in a substantially straight line between the spindle shaft and the driving motor shaft, but willalso adjust the shaft on which the speed change pulley assembly is mounted in a vertical direction to compensate for the shifting of the positions of the effective grooves which carry the motor and spindle belts as they change their positions throughout the speed change movement.

A third object is to provide a bracket of the type mentioned having a pivotbearing plate part supported by an adapter on the drill press 6 Claims. (01. 74-23017) frame; said adapter being removably secured to said plate so that different adapters may be used to attach to different types of drill press frames or columns.

I attain the foregoing objects by means of the devices, construction and combination of parts illustrated in the accompanying drawings, in which Figure 1 is a perspective view of a drill press of the type here concerned to which one of the improved types of brackets and supports is secured;

Figure 2 is a cross-sectional view of a speed change pulley bracket as mounted on a support on a drill press column, drawn on a somewhat larger scale;

Figure 3 is a similar sectional view of a fragmentary portion of a modified form of bracket and bracket support;

Figure 4 is a plan view thereof;

Figure 5 is a plan view of a modified form of drill press bracket support attaching clamp;

Figure 6 is a side, elevational view thereof;

Figure 7 is a plan view of a further modified form of drill press bracket support and attaching adapter;

Figure 8 is a side elevation thereof; and

bracket support showing operating movements thereof.

Similar numerals refer to similar parts in the several views.

Referring to the drawings, 2 indicates the drill press head generally. This is supported on a vertical column 3. The drill press head has a bearing part 5 at the forward part of head 2 which journals the drill press spindle assembly 4. The head 2 is provided with an extensible rear portion 6 on which the driving motor 1 is mounted so that its shaft 8 extends vertically, and carries a drivingpulley 9.

The bracket and support, which is the subject of my improvement, is indicated generally by numeral l0 and consists of an attaching adapter [2 which supports the pivot bearing plate M in a manner such that the pivot boss 15 is offset eccentrically relative to the axis of column 3. It should be understood that the aXis of cylindrical boss I5 is eccentrically disposed relative to the axis of the column 3.

A threaded pivot shaft or pin I 6 is screwed vertically and axially into the center of boss 15. Boss so that its inner end it is disposed over the central opening of the upper end of column 3. This inner end is provided with a boss 23 into which the speed change pulley supporting shaft 22 is affixed.

The speed change pulley assembly is indicated generally by numeral 24. This assembly consists of an upper V belt pulley part 25, a lower V belt pulley part 2.6, and a double-faced .V belt.

pulley part 21 which is axially shiftable between these two pulley parts to provide an upper effective groove 30 and a lower eifective groove 32..

Pulley parts 25 and 26 are pressed onto a bearing sleeve 33, which is journalled on shaftv 22;

shiftable pulley part 2'! slides axially. on the.

central portion 34 of this sleeve, and is also journalled on this central portiom A wholease sembly 24 is therefore free to turn on shaft ,22.

and, as shown in Figure 2, is permitted to slide axially upward on this shaft slightly to accommodate and adjust itself to the horizontal running plane of the belts '33 and 31 (Figure 1). As shown in thisfigure, the driving belt- 36 extends from motor shaft pulley 9 to the upper effective groove 30 of pulley assembly 24, while the driven belt 3? extends from the lower effective groove 32 of said assembly to thespind-le pulley 3|. It is to be noted that in this position the rear bend 38 of driven belt 31-is crowded toward the hub or central portion of pulley assembly 24; and is at the bottom of groove 32, thereby pushing shiftable pulley part 21 upward and crowding the forward bend 39 of driving belt 36 outward toward the rim of the upper effective groove 30. In this position bracket 2! is pivoted so that its inner end carrying boss 20 and shaft 22 is, at the forward end of its travel.

At the outer portion of bracket 2| there is a lug 43, which extends downward over bossand is bored radially relative to shaft Hi and istapped to receive the inner threaded end of operating handle ll. This handle has a ball 42 at'its outer end and bears against shoe 43 at its inner end. This shoe acts as a brake and bears against'the outer curved surface 44' of boss IS.

The position of the bracket indicated in Figure 1 .may be known as the lowesp eed position and this position is indicated in solid lines Figure 9 by letter A. By moving handle 4! forward, the inner end. l8 of bracket 2| will be movedrearwardly to the position indicated'by dotted lines B,in..Figure 9. This is known as the low-speed position. Bracket 2lmay be held in either of these two positions, or any position intermediate them, by screwing handle 4| inwardlyso that.

shoe .43frictionally engages the surfaces MOf bossv [5;

As the bracket 2| is moved from position A to position B it will be noted that since upper pulley part 25'is axially fixed on sleeve 33 the shiftable. pulleypart 21 shiftsaxially downwardly approximately half the width-of belt 35. This belt will tend to be misaligned horizontallyin a downward direction. This would ordinarily cause uneven wear on pulley 9. To ofiset thismisalignment the whole pulley assembly 25 slides upwardly, slightly, on shaft 22. Meanwhile, as belt 31'shifts outwardly toward the rim ofeifective groove 32 it tends to shift downwardly, approximately half the width of the belt. The upward movement of assembly 24 therefore also offsets this shifting movement of belt 37 so that it continues to operate in a horizontal plane and is not misaligned relative to pulley 3|.

This manner of shifting pulley assembly 24 is satisfactory as long as the assembly is light relative to the strength and weight of belts 36 and 31. If, however, this assembly is of greater weight, the arrangement is inefficient.

In order to provide definite mechanical adjustment for the vertical position of the assembly 24 relative to the horizontal operating planes of belts 33 and 31, Iv provide th modiflcation shown in Figures 3jand 4; Here,.zins,tead;of;bracket 2| journalling on the upper portion of shaft l6 itis fixed to the shaft by pin 50. The shaft here designated 13a, turns in boss [5. The threaded portion.llaeoffthiscshaft may be said to journal in the threaded hole of the boss. Therefore as bracket'2l 'is swung relative to the plate [4 it is raised: and lowered: according to the pitch of threads 52 on shaft Ilia. Since it is desired to shift'theassembly upward as the bracket moves from position A to position B the threads 52 can be pitchedso that they .will'carry the bracket up. ward the desired distance.

is flttedinto the opening in; drill press head. 2

through which column'3extends. This adapter: has a boss GIT-which fits-into the opening 6|.in.

thehead. A flange 63 is. provided on the upper side of this boss. The boss-may then be held in place by set screws 64- whichscrew radially v outward-through boss 30' and engage the inner.

surfaceof hole Shin a head 2.

Adapter l2 is provided with a horizontal flange extension: 66 on .one' side which mates with aflange extension 67 on plate I4 and'is secured thereto by screws 68.

Where theheads, or head castings of drill frames, are not provided with a bore-such asshown-atlilg Figure2, an adapter such as shown in Figures 5 and 6'may be used. This adapter 'lllfits over thetop flange or rim H of the head 32 and is held on it by set screws extending radiallythru threaded holes 13. This adapter has-- a flattened flange lfi which is-shaped to receive flanged! of plate l4; The'plate is then held" imposition byscrews 68 similar to those'shown in-Figure 2.

Where the drill press column will not accommodateeither-theform of adapter shown in Fig.-

ure ZonFigures 5 and 6; an adapter is-provided' which-substantially; becomes a, part of the drill press head asshown in Figures 7 and 8. This adapter consists of two spreaderpiecesflfl bolted tdheadpart' B at the front and'to the base .19

ofmotor Tatthe rear. A flat flange 8| is-shaped' to receive flange 61 of plate .M andsecuredby screws fi3whiohare similarto those shown in Figure. 2.

In theforms shown, in Figuresldand. 6, and? and 8,. the, shaft lfiisattached to theplate [4 in the same manner as. isshown inFigureZ,v andbracket .2l operates in the same manner as above described;

In use, all-formsofjthe bracket are pivoted to turn ,or.v swingon or with shaft 16, which is posi-v of, column 3 .islintermediate the axis. of spindle Conversely, the bracket 2! will be lowered when moved. from: position B. to A-.. Sleeve 33 of assembly 24-- is-then securedagainst'axial movement onsh'aftt 22 by collar 53iindi'eated in dotted lines, Figure .1;

As shown in Figure 2, the attaching adapter I22 4 and that of motor shaft 8, and is in alined position between them, the are 83 is also substantially alined between the spindle and motor shaft. line 84 can be made very small by supporting bracket shaft l6 only a few inches transversely from line 84. For the purposes of moving the pulley assembly fore and aft to secure the shifting of the pulley parts necessary to effect the 'speedchanges desired the movement may be said to be substantially in a straight line relative the alinement between the spindle and motor shafts, as indicated by line 84. The arcuate travel is usually two inches or less, and an offset of four to six inches gives an adequately shallow arc. The adapters, shown, and the plate removably attached to them provide a convenient means for supporting shafts It or lGa in the desired eccentrically offset position. In all cases the adapter is olampably attached to the drill press column or head and is made to provide a flange 63 which forms a support to which a similar mating part on plate I4 is removably attached. 9

. There are a large number of drill presses, of

the type mentioned and here concerned, now on.

the market. They are quite similar in all respects, generally, but differ in minor details. To provide means for securing plate [4 in the proper position on the drillpress frame or head, the various adapters are shown. They have the common features that they are screwed to or olampably affixed to a desired part of the drill press frame, and removably secured to the plate by machine screws or their equivalents.

As a whole, the devices here shown provide a convenient and eflicient means for supporting speed change pulleys in an operative position on drill presses of the type above indicated, and provide a means for operating them to attain speed changes desired.

While the parts shown here are preferred forms, it is to be understood thatvarious modifications may be made which could be properly considered as mechanical equivalents of the several parts shown and described.

I claim:

,1. A speed change pulley bracket support, for a drill press having a vertical frame column supporting a frame head having a vertical spindle at its fore end and a vertical motor shaft at its rear end, to carry a speed change pulley assembly fore and aft between said spindle shaft and motor shaft in a substantially straight line, consisting of an adapter olampably attached to said drill press frame, a pivot bearing plate removably attached thereto, having a cylindrical boss with a vertically extended threaded hole therein, a bracket shaft threaded therein, a speed change pulley bracket journalled on said shaft having an inner end extending substantially over said drill press column and a downwardly extending outer end having a threaded radial hole, a vertically extending speed change pulley shaft attached to the inner end of said bracket and extending upward therefrom, a speed change V belt pulley assembly, having an axially shiftable double faced pulley part betweenupper and lower pulley halves journalled on said pulley shaft, a handle having an inner end with a thread formed thereon, and an outer end with a gripping knob thereon, having its inner end screwed into said radial hole in the outer portion of said bracket, and a shoe bearing on the inner end of said handle engagingthe outer curvedsurface of said cylindrical boss on saidpivot bearing plate.

The arcuate movement transversely of 2. In a drill press having a head supported by a tubular vertical column and having a vertical spindle shaft journalled in the portion forward of said column, and a motor with a vertical shaft on the rear portion of said head, a speed change pulley bracket support to carry a V belt speed change pulley assembly fore and aft between said spindle shaft and motor shaft in a shallow arc, consisting of an adapter having a boss clampably secured on said drill press column and having a laterally disposed plate flange; a pivot hearing plate having a flange on its inner end mating with said plate flange on said adapter and removably secured thereto, and a downwardly extending cylindrical boss on said bearing plate at its outer end axially bored and tapped and having a bracket bearing shaft screwed intothe bore of said boss; a speed change pulley bracket journalled on said. shaft having an inner end extending over the mid portion of said drill press column, said inner end of said bracket being movable in a shallow are substantially alined between said spindle shaft and motor shaft; a vertically extending speed change pulley shaft secured to the said inner end of said bracket; said bracket having a lug on the outerend thereof extending outward and downward adjacent the curved outer face of the boss on said bearing plate, provided with a tapped hole extending radially relative to said bearing boss; a speed change V belt pulley assembly journalled on said pulley shaft on said bracket having effective grooves to receive a driving belt and a driven belt; a handle having an outer and an inner end a gripping knob on its outer end and a threaded portion at its inner end screwed into said radial hole in the outer end of said bracket; and a brake shoe bearing against the inner end of said handle frictionally engaging the curved outer surface of said boss on said plate.

3. In a drill press having a head supported by a tubular vertical column and having a vertical spindle shaft journalled in said head forward of i said column and a motor with a vertical shafton the rear portion thereof, a speed change pulley bracket support to carry a V belt speed change pulley assembly fore and aft between said spindle shaft and motor shaft in a shallow arc, consisting of an adapter having a boss olampably secured on said drill press column and having a laterally disposed plate flange; a pivot bearing said plate axially bored and tapped; a bracket holding shaft having a threaded lower portion screwed into the axially threaded bore of the boss on said pivot bearing plate and journalling therein to attain axial movement when rotated; a speed change pulley bracket pinned to said bracket holding shaft having an inner end extending over the mid portion of said drill press column and movable in a shallow are, generated by rotary movement of said bracket holding shaft, and substantially alined between said spindle shaft and motor shaft on said drill press head; said bracket having an outwardly and downward ly extending lug at its outer end disposed adjacent the outer surface of the cylindrical boss on said plate provided with a tapped hole extending radially relative to said cylindrical boss; a vertical speed change pulley shaft attached to and extending upward from the inner end of said bracket; a speed change V belt pulley assem- 7 blyaj ournalledzon said puliey'fshatt -on said bracket haying'sefiective grooves tozreceivenae drivingtfbelt andiai drivem belt a; handler-(haying z a; gripping; knobiiomits outeri'end andithreadediatiitszinner: end-.zinto saidradialiholeaimtlie iouter fen'dmf :said: bracket; and a brake shoe; bearing against the: inner; end. of :said; handle-1 frictionallya engaging; thetcurvedxouterr' surface: of: said: boss: 1 on; said: plate; the: threads: on; thBi-EIOWGI'; portion: off said: bracket-(holding shaft having .5 a: pitch: suffic-ient'il 10;: to raise: and JOWBIL said1bracket3and saidi'; speed; ohangepulley assembly thereon, .throug-houtrspeed:: changingamoveinent; sozthat the horizontal planes. of the'efiectivergrooveszof saidxvsb'elt speed change pulley-i assemblysaretnot altered duringzsaid speed: change amovementf of isaiob bracket;

4eInzaxdrill. pressz havingea:v frame including at; headisupportedby eaztubularavertical :cclummand: having: a: vertical: spindle shaft"; at the fore .2 sides of; said columnxand'sv aitverticall driving-i shaft-ion; theratt' side'vof saidicolumn;asspeedzchange pulley; bracket; and :bracket:support-consisting of a spivotibearing, plate: having arri inner pjortion'i and: an; outer portion a vertically: extending: cylindrical:

bosszpositioned onthe out.er.ipor-tiontrofrsaid plate;

attaching meansz for: securing a said: plate to; thes: upper :part of-uthezframe-vof .aedrillzapressaso. that: the;axisr of saidabosszis' offset eccentrically relai tive stor-said frame-x column; a; bracket: bearing sliaft extending; axially'pfrom;saidicylindrica1 boss; a speed: change pulley; bracketa composed ofian; elongated body; havingea pivot:bearingzshaft'ree ce-ivingihole in its" central portion, an: upwardly? extending-speed changewpulleyi shattsat one-send. andianwoutwardly and downwardly;-extending lug: atyitseothen end? having a threaded bore: to::;re.-.- ceivelan operatinghandle: extendingeradiall'y rela+-- tivea to1, theaxis of said; pivot bearing: shaft; a 1 handlee rod having; a: threaded? portion: at; one: end screwable into the bOIGc-innSflidxltlg; a: shoe: bearing; on .the threaded end portion of :saidrhandleerodand frictionallypengaging thgvgu-ter curved i, surface-lof-isaid cylindrical 2 boss: and: as gripping;- knob-1 onritswopposit end; and a V belt. speedrz changer pulley :assembly; of rtype-zhaving;v a double: f acedpull'eye part axially shiftable betweenw twoz pulley: parts; having their faceswadjacent:the ree speotiverfacesnof-isaid shiftab-le pulley part; to: form upper and: lower? efiectivei V2? belt grooves:- jour-nailed onthesp'eed change; pulley shaftton'; said:- bracket; said bracket being j our-called: on": said apivot :bearing rsh-aft to pivot thereonwhen;

moved? by.:- said :handle and: to swing ;said:: speed change-pulleys assemblyyinashallow arczsub-rstantially alined. between -saiddrivirrgw shaft and-2i said-gspindle shaftl.

e rn a drill-press'haying aiira-m'e,rinelud ingial head supportedrby a tubular vertical column and having a vertical spindle-shaft at the forezsicle -.o-f-. saiducolumn and a vertical driving shaft on' the aftiside .-ofsaidvico1umn,- aespeed change pulley bracket and bracket support consistingio-tza-apivot bearing plate :havings. an. inner portion and; outer portion, a vertically extending; cylindricalboss positioned on therouter portion. of said-- plate;-v attaching meanstfor securing. said; plate: .-to= the upperpart of the. frame of a rilrillpressz-so.v that; thesaxistof said-.boss. issofiset eeccentricallyrela-- tivetosaid frame-column; aibraoketpivot-.bear--- ing. shaft threaded axially into-said cylind-rical. boss; axspeed' change pulley br-acket central-lynat-itached to said: pivotbearingyshaft, composedof: an elongated body, having .anin-nerend and .an outer end, ian.-upwardly,-- extending speedschangee pulleyishaft'at itshinner' end, andian outwardly; 7

andsdownwardlyrextending lug-sat its oute'rfend having a. thre aded borezi to. :receive'f an; operatingz: handle iextendingztradially; relativeitdthe axis of said pivot libearing iashandleahaying:anrinner .en'di v. and:.an:outer encl athreaded:portioncatfits innert'. endxscrewable into-:the borezinzlsaid :lugy. at shoes bearing:on?the:inner:endtofzsaidthandleandtfrim tionally engagingthe outer curved: surface of said: cylindrical boss andi'azgripping knob on the outer-.1 end;-:of:t said handle;- and :a' V' belt speedzchange: pulley: assembly of 1 type :2 having a1d0uble5: faced: pulley pa-rt'; axially sliiftahle between atwoiipull'ey partsahaving their faces adjacent theirespectivei: faces .of said shiftablespulleypartitoiform upper? and: lowereffectivezv belt grooveslj ournalledrlorr; the .speed'; change :pulley shaft';'on'.said;. bracket; said bracket ibeing' a-ffixed stoiisaid .pivot 'bearin'ga? shaft .to turntherewith; and saidlpivotbearirrgzi shaft having: its; lower portion: threaded-axially:

into: the: boss on: saidisupportl so a's tot-journal:

on said -threads; pivotir'rgjsaidibracket so' that said:

pulley assemblyrisiswungrima shallowerci sub; Y

stantially alinedvrbetween saidtspindle:shaftfand; motorzshaft; and istiraised.iand loweredithrougli out; saidiswinging: a motion so that thesmiddlei of; the effective grooves :of :said pulley assembly re:- main inz'the sameJhOriZOntal planethroughout said movement:

6; In: a drill.pressthavingiarheadrsupported by l a tubular vertical 'colurnnand .havingt azverticat spindle 'sh'afti journalld inathet: portion. thereof forward ofssaidlcolurn'n', and'ia motor with a-iv'ertical shaft'onitheirrear portionithereof; a speed. change pulley bracket support toicarry' al-v beltl i speed change pulley assembly fore v and aft between said: spindlewshaft'iandamotor shaft in? a i shallow arc; consisting :of an. adapter having: at boss. clampablrp secured. on i said drill press column andihaving-a laterallydisposed platafiange;

a bearing plate having an inner end andvan ou-ter end, .a'; flange: onxitstinner. endlmatingl said; plate flange on said adapter and. removably secured thereto; and a vertically extending cylindrical! boss at theouteriendaof =sa-idb'earinglplate, axia1-'-- 1y bored and tapped; a bracket bearin'gfshafti screwed into the bore in said boss on said'plate; a speed change pulley bracket journalle'd on said bracket shaft having an inner end and anouter end; a vertical speed change pulley shaftfoni-saidd inner end of said pull'ey J bracket, d-isp'osed" overa themid-portion of said drill ipressi-c'olumn and; movable in' a shallow-arc between said-drill spin die shaft 'an'dsaid: motor shaft; alugon theouterifl end of said. pulley bracket iextending outwardly -and'xiownwardly, adjacent said boss onsaid: beariing: plate having a tapped :horizontal I hole; ex, tending raoli'ally relative to said lcylindrical'boss; a speed change .zV- belt 'pulleylassernbly," journall'edf on said pulley shaft; having. efiectives groovesgzto receive. a drivingbelt Iandxa driven 'b'elt aihamileu having an outer end: andfanrinnenend;afthreaddt portion on its 7: said: inner end; .and" a2 knobzonn its". outer: end,. having: said threaded portionz screwed: into" the-threaded holeiirr iSaidf bracket";

lug; ancha shoex bearing zon the :inner'zendi of:

said handleand frictionally engaging the curved outer surface of said boss on said bearing p-late=' References:aoitediin .the 'fil'eziof 7 this patent UNITED STATES PATENTS Number Name Date;

2,073,704 Mitchell Mar.- 16, .1937 2,561,545 Wallace f Ju1y ;-24, .1951 c.

2,566,579. Nichols? .Sept.:4 1951 

